Sparking plug.



K. C. WIDEEN. SPARKING PLUG. APPLIoATIoN FILED 1AN.25,1906.

967,283. Patented Aug. 16, 1910.

W-tnea Ses Q Invenor, @/Muw W/ Knuf Cf T//deen m im? I *dwq @y Aitor@ UNITED STATES PATENT KNUT C. WIDEEN, OF NEW YORK, N. Y., ASSIGNOR TO ARC SPARK MFG. CO., OF NEW- YORK, N. Y., A CORPORATION OF NEW`YORK.v

SPARKING PLUG.

This invention relates to the construction of devices for the support of the electric sparking points in the cylinders of explosive origines.

One object of the invention is to provide an insulating tube which separates the two conducting members of the sparking plug, and in which sooting of the exposed surface of the insulating tube with the consequent electrical surface creepage and short circuiting is lessened by the shielding of a part of such surface.

A further object-of the invention is to increase the durability of the insulating tubes by enlarging or providing the tubes with heads at the exposed ends which adjoin the sparking points.

A further object of the invention is to reduce the liability to electrical surface creepage by corrugation and consequent extension. of the length yof exposed surface lietween the nearest points of .contact of the two conducting memberswith the insulating tube.

In the accompanying sheet of drawings, which forms a part of this application, Figure l is an external view of a sparking plug embodying my invention. Fig. 2 is a longitudinal section through the plug in place in the wall of an engine cylinder.

i The sparking plug comprises a metal bushing A, exteriorly screw-threaded for.inser tion in the wall of the cylinder of an explosive engine. In the assembled plug the interior of this bushing at the exteriorlythreaded end constitutes a chamber c. At the bottom of the chamber is an annular shoulder (l, and the bushing at the other end is interior-ly threaded. A refractory tube B is contained within the bushing and projects from each end thereof, it having an enlarged annular collar 7c tlereon which lits snugly within the bushing between the annular shoulder (l on the latter, and a threaded collar C screwed into the bushing from the exterior end thereof. The inner end of the tube consists of a hemispherical head li Specification of Letters Patent.

Patented Aug. 16, 1910.

Application led January 25, 1906. v Serial No. 297,730.

of as large a diameter as will permit its insertion through the bushing, it beingrsubstantially of a diameter equal to the interior diameter of the latter, the head being united to the part of the'tube which is surrounded by t-he collar lo by a neck portion, which is of less diameter than the diameter of the bushing, so that an annular chamber c surrounds such portion of the tube, the neck portion being surrounded by undulatory grooves, whereby its surface is formed into a series of gentle curves n. The enlarged head is entirely located beyond the inner end of the bushing so that while it covers the annular chamber c itis out of contact with the innerend of the bushing. A bentwire zf'which is firmly secured to the rim of the bushing, lies across the axis of the bushing in front of the head of the insulating tube, and a conducting member M passes through the insulating tube and has an exposed wire-end m in proximity to the bent wire. The conducting member is firmly secured in the insulating tube and threaded at the end opposite to the end with the wire end m for a binding nut R, by which electrical connection may -be made. The two wires are. the sparking points of the sparking plug, and each wire, with the metal parts to which it is attached, constitutes one of the conducting inemberskof the sparking plug.

The spark takes place between the end of the exposed wireend of the conducting member and a point on the bent wire secured to the rim of the bushing, which is in proximity thereto. lVhen the sparking plug is in place in the wall of the cylinder, these wires project:` within the` cylinder. It has been found that the explosion frequently leaves a residue of solid mattei" as unconsumed oil and carbon, which is projected by the shock of explosion within the cylinder in all directions and causes all surfaces which may be exposed to the interior of the cylinder to become coated. As such matter has a certain amount of electrical conductivity, the coating of the surfaces of the insulatingtubes causes short circuits, which interfere with proper sparking. This objectionable action is mitigated by the construction above set forth, first in the provision of the head portion on the insulating tube, which substantially covers the opening to the chamber of the plug suiiciently to shield the neck portio, and which due to its rounded form, deiiects such matter sidewise across the mouth of the chamber instead of permitting it to enter therein, and this action is further mitigated by reason of the circumferential corrugation of the neck portion7 whereby the extent of surface which must be coated` before there can be a short circuit is considerably extended. What I claim as my invention and desire to secure by Letters Patent7 is In a sparking plug, the combination of a chambered lug, an insulating tube contained withln the plug and having an enlarged body portion thereon held within the plug, and having a hemispherical head not less than the diameter of the chamber of the plug located opposite to and havingits larg'- est diameter beyond the mouth of the plug and out of Contact therewith, connected with the enlarged body portion of the tube by a corru ated neck portion having a diameter less t an the diameter of the chamber of the plug and separated therefrom by an annular chamber.

Signed by me at New York city, N.Y., this 24th day of January, 1906.

KNUT o. WIDEENQ Witnesses SAMUEL W. BALCH,

HUGH H. SENIOR. 

